Method of manufacturing electrolytic or electric-light carbons.



UNITED STATES PATENT OFFICE.

HERBERT H. DOW, OF MIDLAND, MICHIGAN.

METHOD OF MANUFACTURING ELECTROLYTIC 0R ELECTRIC-LIGHT CARBDNS.

SPECIFICATION forming part of Letters Patent No. 718,437, dated January 13, 1903.

Application filed November 6, 1899. Renewed April 13, 1901. Serial Na 55,789. (No specimens.)

$0 on whom it may concern.-

Be it known that I, HERBERT H. Dow, a citizen of the United States, and a resident of Midland, county of Midland, and State of Michigan, have invented a new and useful Improvement in Methods of Manufactu ring Electrolytic or Electric-Light Carbons, of which the following is a specification, the principle of the invention being herein explained and the best mode in which I have'contemplated applying that principle, so as to distinguish it from other inventions.

My invention relates to the production of a more perfect and uniform carbon for use in electrolytic processes or for usein electricarc lamps and also to cheapen the cost of such production.

The following description sets forth in detail one mode of carrying out the invention, such disclosed mode constituting but one of various ways in which the principle of the invention may be used.

The coke or other carbonaceous material is first ground to a powder and injected into a closed chamberin to which a suitable bindersuch as tar, pitch, or the likehas been previously injected and exists in the form of a vapor or gas. Such injection may be accomplished by sprinkling the finely-ground carbonaceous material from the top of the chamher, so as to form a dust in the vaporous binder. Such dust settles to the bottom; but before reaching same each particle of dust which is caused to be colder than the surrounding vapor, as will hereinafter appear, has condensed upon its surface a film of the material which existed as avapor just prior to such condensation. This film increases in thickness with the specific heatabsorbing capacity of the carbon particle to which it attaches itself. Therefore a large particle would condense more binder than would a small particle, and hence by the above-described method the proportion of binder to carbonaceous material in the resulting product is uniformly maintained throughout the whole mass of material treated. The carbonaceous material in its comminuted form mingling with the vaporized tar or pitch permits of an intimate mixture of the particles of the two substances and more intimate and uniform than is possible to obtain by mechanically mixing in solid form. In this condition the temperature of the carbonaceous material is caused to be less than that of the binder, such difference of temperature being readily obtained, inasmuch as it is usually necessary to apply heat to such binder in order to suitably vaporize it; The commingling of the particles of carbon and binder hence results in the condensation of the binder upon the surface of such particles,the amount of such deposit depending upon the relative temperatures of the carbon and binder. The covered particles of carbon now being permitted to settle in the chamber a deposit of material is obtained ready to be molded and baked into the required form.

It is also readily seen that the order of procedure may be varied-that is, the carbonaceous material first placed in the chamber and the vaporous or gaseous binder injected into it, or the two may be simultaneously injected, or the binder may be vaporized in the chamber and the carbonaceous material thereupon injected, the principle of the invention remaining the same in all cases.

By regulating the relative temperatures of the carbon particles and the vaporous binder anyamount of binder may be caused to adhere to the carbon as is required to produce an efficient combination consistent with the most economical result possible to obtain.

For electrolytic purposes carbons should be as dense as it is practical to make them and also as. free as possible from hydrocarbons of every kind. Ordinary arc-light carbons contain more hydrocarbons and are also more porous than they should be for electrolytic use. This is due mainly to the fact that every particle of pulverized carbon cannot receive enough pitch to cement it without providing a great excess of pitch for some of the other particles when simply mechanical mixing is depended upon. By my method each particle will receive an amount of pitch in proportion to its size, thus making it possible to use a minimum amount of pitch, and consequentlya minimum amount of porosity exists. By my method each particle of carbon will receive an amount of binder in proportion to its size and uniformly distributed over its surface, thus making it possible to use a minimum amount of binder. As a con sequence of this uniform distribution of binder on the carbon particles the finished carbon is of uniform texture and greatest possible density, the spaces between the particles being reduced to a minimum. By my method more uniform results and better conductivity with the same amount of baking can be obtained.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the steps herein disclosed, provided the step or steps covered by any one of the following claims be employed.

I therefore particularly point out and distinctly claim as my invention-- 1. The step in the manufacture of carbons, which consists in the depositing of vaporous binder upon the carbonaceous particles, substantially as set forth.

2. The step in the manufacture of carbons, which consists in mingling comminuted carbonaceous material with a binder in the form of a vapor or gas, substantially as set forth.

3. The step in the manufacture of carbons, which consists in mingling comminuted carbonaceous material With a binder in the form of a vapor or gas having a temperature greater than that of said carbonaceous material, substantially as set forth.

4. The process of manufacturing carbons, which consists in mingling comminuted carbonaceous material with a binder in the form of a vapor or gas and having a temperature greater than that of said carbonaceous material, permitting such material to settle, and molding and baking the resultant deposit, substantially as set forth.

Signed by me this 18th day of October, 1899.

HERBERT H. DOW.

Attest:

D. T. DAVIES, A. E. MERKEL. 

